There are ground-based electrical power supply systems which allow vehicles of the tramway type to capture, via a friction shoe, the electrical traction energy required to move them and unattractive aerial lines to be dispensed with, in particular in the region of junctions.
Such a system is described in the patent application EP 1 043 186 A 1. The system described involves a ground-based electrical power supply assembly which comprises a series of segments of conductive contact tracks which are mutually isolated and at least partially exposed, an electrical line which is intended to be permanently supplied with electrical power, means which are capable of selectively connecting the track segments to the electrical line and track supports of an insulating material which each have a cross-section which is generally “I”-shaped.
On the upper portion of the supports, there are provided two parallel grooves, which are arranged in a symmetrical manner about a longitudinal center plane which is perpendicular relative to the extension plane of the upper portion, and which are capable of receiving an alternating sequence of conducting and insulating elements in the form of bars.
In the web of the profile-member of the supports, there are arranged four internal rectangular passages which are capable of receiving metal bars of a high-voltage electrical line. The passages are arranged in pairs at one side and the other of a longitudinal center plane which is orthogonal relative to the upper surface which separates the profile-member of the support into two, in an offset manner at each side.
At one side and the other of the longitudinal center plane there is engraved a detection notch, the two notches forming a pair which is intended to receive cables of a detection loop of a nearby magnetic field.
With this system, the communication signal supported by a magnetic field of the detection loop is interfered by spurious signals which are produced inside the two bars.
The technical problem addressed is to reduce the intensity of the spurious signals which interfere the communication signal supported by the magnetic field of the detection loop.